The automotive industry is increasing its pace in product development. At the same time an increasing number of mechatronic systems are deployed in the final product. These systems are developed virtually and have to be integrated in purpose driven integration platforms with purpose driven fidelity simulation models. The introduction of an interface standard, the so called functional mock-up interface (FMI), is an enabler for this process to be deployed on a wider scale.
The used simulation models of physical systems are created in domain specific authoring tools. These tools are used for its fit for purpose numerical solvers. Because the physical systems mainly are modelled in continuous time domain, the resulting co-simulation models are in fact sampled systems. For this reason it is common knowledge to limit the bandwidth of the modeled system to fit well within the Nyquist frequency.
However, co-simulation of, for instance, mechanical systems have strongly coupled interfaces. In the particular case when motion signals are input, resulting forces and/or torques (or vice versa) have to be fed back. But, the applied motions (or forces and/or torques) create continuous time step responses which induce noise with a relatively large bandwidth.
EP2680157 addresses the above issues of a co-simulation system by computing a Jacobian matrix based on output derivatives, wherein the output derivatives are based on corresponding state variable derivatives related to corresponding first input variables for each of a plurality of subsystems. The method disclosed by EP2680157 also includes modifying the first input variables and computing second input variables and residuals for each of the plurality of subsystems based on corresponding state variable derivatives.
However, even though the suggested method of EP2680157 may solve some of the present problems related to co-simulation, the method described in EP2680157 would require complex mathematical procedures. Moreover, the method requires detailed knowledge of the properties of the subsystems, which is not always possible when connecting subsystems represented by different commercial tools.
Accordingly, there is a need for a simplified method of improving the connectivity between subsystems in a co-simulation system.